Sens. Ron Wyden and Jeff Merkley are opposed to a proposed Coquille Indian Tribe casino in Medford.

In a letter to Kevin Washburn, assistant secretary of Indian Affairs with the U.S. Department of the Interior, the senators criticized the proposal because it runs counter to Oregon’s policy of one casino per tribe.

The Cow Creek Band of Umpqua Indians, which operates a casino on Interstate 5 about 70 miles north of the city, has paid $300 a month for a billboard north of Medford that opposes the Coquille’s proposal. The sign proclaims, “No Reservation Shopping” — which refers to tribes looking to build casinos far from reservations.